1. Field of the Invention
The present invention relates to a method and an apparatus for determining a kind of an external connection device connected to a portable terminal by detecting a signal transmitted to and received from the external connection device, and for performing an operation according to the determined kind of the external connection device.
2. Discussion of the Background
A portable terminal may have many applications because of easy portability, ability to store various programs, and excellent utility. There may be increased numbers of users of a portable terminal because voice calling is enabled during movement of an individual user.
Early in the development of portable terminals, batteries and other devices were very large in size in order to achieve stability, which made the above-mentioned portable terminals heavy and large which decreased its utility as a portable terminal. Recently the devices and the battery have been improved, so that a portable terminal may be very light, thinner, and small in size.
The portable terminal may have a charging mode for charging the battery and a communication mode for data communication. The portable terminal may be connected to a terminal adaptor (TA) to support the charging mode and may be connected to an external device to support the communication mode.
To charge the portable terminal, a data cable connecting the portable terminal to the TA may be provided. Moreover, the portable terminal may include a connector interface to which the data cable is connected. This connector interface may be used as a path through which the TA of the portable terminal is connected and as a path for supporting universal serial bus (USB) communication of the portable terminal.
However, in an existing portable terminal, a power source used in the charging mode may be different from that used in the communication mode. Thus, if the portable terminal recognizes the external connection device as the TA when the portable terminal is connected to the external connection device through the data cable to support the communication mode, an error may be generated from the user interface (UI) of the portable terminal. Moreover, when electric power more than the maximal current regulated under a standard is supplied, an error may be generated from the external connection device.
For example, in a case when the external connection device is a highly integrated device affected even by a minute change of electric power such as a laptop computer, an MP3 player, and the like, when the portable terminal transmits and receives signals to and from the external device using a power source in the charging mode, a central processing unit and peripheral hardware of the portable terminal may be damaged.
Therefore, the portable terminal should be capable of determining whether the external connection device is a terminal adaptor or other external device. The portable terminal should determine whether a device connected thereto through the data cable is a terminal adaptor for charging the portable terminal or an external device for USB data communication with the portable terminal.